BY THE NUMBERS

34.5: Tennessee returns 11 defensive linemen who have combined for 34.5 career sacks and 70 career tackles for loss. Those totals include minimal contributions from younger players like Kahlil McKenzie, Shy Tuttle and Kyle Phillips. No wonder new defensive coordinator Bob Shoop is excited about the defensive line he’s inheriting.

151.6: The Vols ranked ninth in the Southeastern Conference in rushing defense last season, allowing 151.6 yards per game. Only Arkansas (275) and Vanderbilt (202) cracked the 200-yard mark on Tennessee, however. Tennessee allowed 168 yards per game in 2014.

19: Defensive linemen accounted for that many of Tennessee’s 30 sacks and 41.5 of the team’s 75 tackles for loss as the Vols finished tied for fifth and 10th in the SEC in those two categories.

STAR POWER

The next NFL jersey to go up in the room dedicated to the program's first-round draft picks in Tennessee's complex likely will be Derek Barnett's, presuming the star defensive end turns pro after this season.

Barnett, who stands intimidatingly with his arms crossed on the cover of Tennessee's 2016 media guide, headlines a deep and talented front the Volunteers believe can transform their defense into a championship unit.

A stronger start from its most talented player certainly would help. Tennessee totaled 65 sacks the past two seasons, and Barnett had 20 by himself with a pair of 10-sack seasons. But as a freshman in 2014 he didn't make his first sack until the fifth game of the season. In 2015 he had one sack in the first four games before registering nine in the final eight.

With a career season, Barnett could join elite company in Vols history. He needs 13 sacks to break Reggie White's career record, and with 21 tackles for loss he would pass Leonard Little for that career record.

PROMISING PROSPECTS

So much was expected of defensive tackle Kahlil McKenzie when he arrived last summer as one of the nation's top recruits, and that's still the case.

Weight management has been a chore for the big man, who's down to 325 pounds after playing last season in the 345-350 range. The weight loss should enhance McKenzie's conditioning and quickness, and the Vols expect disruption of opposing backfields to follow.

Despite not playing his senior year of high school, McKenzie made 24 tackles with one sack as a freshman. His role increased as the season progressed, but much more is expected now.

Shy Tuttle was ahead of McKenzie when he got hurt last season, but a significant injury has clouded his short- and long-term futures.

Kyle Phillips was the story of preseason camp last season, but the former five-star prospect never got going due to injuries and had his freshman season cut short by shoulder surgery. When healthy, he gives Tennessee another explosive pass rusher.

Second-year players Austin Smith and Andrew Butcher also are coming off injuries.

With Barnett rarely leaving the field and more experience ahead of him, it's hard to tell how many snaps Darrell Taylor will get this season, but the redshirt freshman turned heads this spring.

Tennessee preseason preview:

The wave of preseason hype is cresting the highest for Jonathan Kongbo, the junior college transfer the Vols beat out Ole Miss, Southern California and others to land on signing day. The perception of Tennessee's 2016 class changed when he hopped on board. Now he's the player fans will be most eager to see and hear about during training camp.

Kongbo's athleticism is obvious — he had 55 tackles and 11 sacks last year at Arizona Western College — and he's up to 282 pounds. The added weight opens the door for Kongbo to slide inside on some downs. Still, though raw, Kongbo's strength is his speed off the edge as a pass rusher, and the Vols hope he can take that role quickly.

STRONG SUITS

Tennessee has as much quality depth on the defensive line as it has had in some time.

Beyond Barnett, there are proven veterans. Corey Vereen hopes to build off a strong close to last season, and Danny O'Brien and Kendal Vickers were solid, unsung defensive tackles who can handle the dirty work. Role players like LaTroy Lewis and Dimarya Mixon are capable of getting the job done as well.

There's young talent with the likes of McKenzie and Tuttle (if healthy) inside and Phillips, Taylor and Kongbo off the edge.

The challenge for Shoop and defensive line coach Steve Stripling will be identifying the combination that gives the Vols their most disruptive lineup for each situation.

QUESTION MARKS

Nearly every time he's done an interview this offseason, Vols coach Butch Jones has been asked about Tuttle's progress in his recovery from a broken leg and torn ankle ligaments. Tuttle only resumed running last week, and his availability for the start of practice (and beyond) is unknown.

With Alexis Johnson indefinitely suspended after being arrested in February, Tennessee could enter the season with only McKenzie, O'Brien, Vickers and Quay Picou, a 277-pound sophomore, as their only available scholarship tackles.

Tennessee's defense becomes less formidable without Tuttle, and the Vols need his contributions.